Why do I have pain?

Pain is an effective and essential part of life. It protects you and alerts you to danger, often before you are injured. If you are injured, pain can make you move and behave differently which is essential for healing.

Does pain mean that I am injured?

Most commonly, your experience pain when your body's alarm system alerts your brain to actual or potential tissue damage. But pain isn't always proportional to the amount of danger in the tissue. It is possible to sustain an injury without experiencing pain, or to have pain even though no physical problems exist.

What can I do about my pain?

Understanding pain helps you to deal with it effectively. If pain persists it can be difficult to see how it can be serving a useful purpose, but even when pain is chronic it happens because your brain has concluded that your tissue is threatened and is in need of protection. The trick is finding out why your brain has come to this conclusion.

What is my pain telling me?

Often times pain has an important message for you. For example, if you have been sitting in the same position for a long time your brain will receive messages that acid is building up in your muscles and it will hopefully encourage you to get up and move. 

Emotional pain

All pain involves thoughts and emotional contributions. 

Bulging discs

In low back pain, research has shown that the amount of nerve and disc damage rarely relates to the amount of pain experienced. Many people have scary sounding disc bulges or pinched nerves yet never have any symptoms. Many of these changes in the tissue are a normal part of being alive and don't have to hurt. 

What factors contribute to pain?

Pain depends on many different factors and it is the brain that decides whether on not something hurts. 

A lack of knowledge can increase fear and increase pain. Unexplained and ongoing pain and deep injuries you can't see, unlike most skin injuries, increase the threat of pain. 

Phantom pain

You don't have to have a body part to have pain there. Phantom limb pain tells us about the virtual limb inside the brain. In phantom leg pain, although the leg is missing, the virtual leg and the relationship of the leg to the rest of the body is still represented in the brain. Groups of neurones devoted to body parts are in a thin strip of brain above your ear. 

Your danger alarm system

You have a sophisticated danger alarm system that can detect changes that are big enough to be dangerous. If you place your hand over a hot surface, the increasing warmth will begin to ring a few bells and a few messages of impending danger will be sent from your hand. The process that would eventually turn the danger messages into pain is far more complex. 

Your sensors

Throughout your body there are millions of sensors. Some sense just mechanical changes, such as a pinch or pressure. Some sense just temperature changes. Some respond to chemical changes, like acid building up in your tissues. When triggered, these sensors send an electrical impulse into your nervous system.  These sensors, along with the sensors in your eyes (light), ears (sound waves), and nose (chemicals in the air). What we experience is the brains construction of events, which is based on its evaluation of all the information available to it (not just danger messages). ​

Thoughts trigger sensors too

Most sensors are in your brain. They are specially suited to chemical activation. All sorts of thoughts can make alarm bells in the brain ring.

Your pain sensitivity is continually changing

Your current level of sensitivity is not fixed. The life of a sensor is short. They only live a few days and then they are replaced by new sensors. This means your sensitivity is continually changing. 

There are NO pain messages

Nociception is neither sufficent nor necessary for pain.

Your nervous systems messages

Action potentials are the way your nervous system carries messages, an action potential is a single message. If enough sensors open and action potential is reached and a message is sent. The messages only say danger, they do not say pain. The brain has to receive these messages and analyse them. 

Messages meet the spinal cord

Danger messages stop at the synapse, releasing chemicals into it.

The drug cabinet in your brain

Your brain can send messages down to dampen the alarm signals. 

The orchestra in your brain

Think of your brain as an orchestra. It can play thousands of songs. Pain can be thought of as one tune palyed by the orchestra. 

Full Circle

Messages received by the brain don't end there. The brain makes value judgements on the inputs and responds. A pain experience is often associated with altered activity of many bodily systems. These systems respond best for short periods of time. Over extended periods of time, as in chronic pain, sustained activation of these systems can cause other problems (discussed in chapter 4). 

2 Recap

Danger sensors are scattered all over the body. 
When the excitement level within a neuron reaches the critical level, a message is sent towards the spinal cord. 
When a danger message reaches the spinal cord it causes release of excitatory chemicals into the synapse.
Sensors in the danger messenger neuron are activated by those excitatory chemicals and when the excitement level of the danger messenger neuron reaches the critical level a danger message is sent to the brain. 
The message is processed throughout the brain and if the brain concludes you are in danger and you need to take action , it will produce pain.
The brain activates several systems that work together to get you out of danger.